I think we've(especially me) have got a long way to go before breaking in all the drivetrain components. Emission requirements, increased rolling resistance(oversized tires),and load(my camper) certainly play into the equation. A Smarty is in the future for me. It needs more poop and potential warranty denial makes Marco's invention the only option.
Ok... . so whats marco's invention?
also as a guy with highly modded jeep and former 4wd shop employee that has run em all I can tell you its not so much as to the rolling resistance. Its rolling resistance plus the added rotational mass. Swampers are really heavy and suck up mpg. some don't roll very well especially the taller the sidewall the smaller the wheel. then heres learning experience that taught me quite a bit about rolling resistance. if you take a bias ply swamper for instance and you carve it out to increase tire flex for increased bite while rock crawling and you drive the jeep with those tires around daily (I used to do 95mph on the carved tires to my GF's house every weekend back in the day). then you make the switch to a tire such as a goodyear MTR on the same rearend ratios (4. 10, 33's, 6 banger) then you will be amazed in the difference in power and mpg you'll be getting. SO for tires No bias plys and unless you want it up there go big. but those off you who want to drop rpms change the stinking rearend ratios(make sure to use a quality gear and a good shop). And if you are going to be changing ratios drop tire size too with a higher ratio gear (smaller number). This will decrease rolling resistance since you wil have less sidewall to wheel ratio and smaller tire will normally yeild less rolling mass.
I personally am a 4WD guy but sadly I think I might end up fabricating ACOS among other stuff and drop the front. Also I will not consider a offroad bumper for instance roadarmor since I want that airdam (valence, what ever several names) to keep air from going under the truck. sure it will cost me on those late at night (or should I say early morning of a week night) offroad recovery calls I get but I will just have to remove the winch from the jeep and install it in the hitch. Also more diesel guys should be considering the SRT body conversions (parts sold from dealer) just dont use the hood scoop air intake. You want a cowl induction hood to try to throw the air over the window shield. Also unless you a fabricator run the bed covers. Simply removing tailgate actually yeilds more aerodrag in the windtunnel. If you are a fabricator NASA (as in the well funded space nerds) says the magic number for aerodynamics is 23 degrees, so consider fabbing up a nice looking attachemnt to go in the hitch (when not towing) to change the rear of the body angle from 90 degrees to 23 degrees but dont forget lighting and such. also make a attachment that hitch pins on to change aero from top of cab to bed cover, magic number 23 degrees. But You only need aerodynamics at 68 mph and higher. oh and that import tailgating you is a good thing since he is taking away the air disturbance behind you and making it his problem but he gains from tailgating you so its win win situation. And every idiot knows about tailgating truckers. Just make sure they can either see you in mirrors by staying over or if they want to try to get you from behind them simply insist no matter where they go and even if they slow down. Dont take their driving games for shtit. But then again if you are the guy on the cell phone playing with the radio, talking to you buddy, got kids in the back then respect the truckers requests.
Synthetic fluids every were you can. one exception to that: I went to jiffy lube and the shop manager was trying to sell me 5w-40 synthetic oil for my diesel power cummins. I don't know if you guys change your own oil or work in racing industry building engines, But I will sure as hell tell you cummins calls for 15W-40 and they dont come from factory with synthetic. so why the hell would I even consider putting "water" in my oil pan to lube and cool my engine???????? If you go to walmart you will see they dont normally have 15w-40. I believe reason being is 15w-40 is industry standard for diesels. If I can remember correctly the VW Passat uses 5W (something oil) and I seriously dont that the bottom end of those things are under the pressure a diesel bottomend is under. SO what I am saying tell the jiffy lube people they lost their mind and you are not putting 5w-40 synthetic 'water" in your crankcase unless they wish to provide customer loaner vehicle while they pay to have a new engine put in then reimburse you for the rediculous fuel economy while breaking int he diesel. I believe they wont pull that stunt with anyone ever again. And I sure as hell made sure I sat there in the shop right next to the truck baby sitting them while they changed my fluids. Next time around I hope i have a shop put up with a hazardous waste tank out back.
for additional economy use AFE stage 2, Biggest exhaust you can afford but remember that aeros over the cab will pull exhaust from stacks at speed (but sssh dont tell) Change out the crappy stock turbo that is by no means efficient, change out injectors to better quality that stock diesel dynamics stage 1 or better injectors, keep the truck as empty as you can at all times, keep tires inflated to max on sidewall (if the ride is rough consider a different tire load rating or removing some of the spring pack and replace with timbren, or deal with it rough until it softens up. when I bought mine used with 45K the suspension went from hopping and skipping at 70mph on concrete seams to alot nicer just letting it break in), well its been too long since I actually fired up my truck so I beleive I am tapped out from what is ont he top of my head until I finally get all my parts to get my transmission built up and fix the odometer.
BUT HERES ONE MORE SUGGESTION. IF YOU HAVE A 4WD TRUCK AND THE ODOMETER TURNS 666 DIG TWO HOLES IN THE BACKYARD AND BACK THE TRUCK IN THEM AND THEN SET THE CRUISE CONTROL AT A HIGH RATE OF SPEED. ITS SAFE TO HAVE THE TRUCK STUCK THEN IT IS ON JACKSTANDS WHEN YOU ARE DEALING WITH THE DEVILS NUMBERS. THEN WHEN YOU ARE AWAY FROM THE 666 THEN POP IT IN 4WD AND DRIVE IT RIGHT OUT. I have been buried dragging front and rear differentials in the I have even had the front housing like a bulldozer blade and I have never gotten stuck with the exception to playing on the beach with 8,000lbs and alot of torque. but thats a long story you can PM me about if you wanna here how I got my butt chewed out for unfounded legality concerns in a designated ORV zone in a national park.